/Engine/Source/Runtime/Engine/Public/GPUSkinVertexFactory.h
Vertex factory with vertex stream components for GPU-skinned streams. This enables Passthrough mode where vertices have been pre-skinned. Individual vertex attributes can be flagged so that they can be overriden by externally owned buffers.
class FGPUSkinPassthroughVertexFactory : public [FLocalVertexFactory](API\Runtime\Engine\FLocalVertexFactory)